The present invention relates to a method and apparatus for manufacturing a semiconductor device made by forming a thin film on a substrate, such as a thin-film photovoltaic module.
To manufacture a thin-film photovoltaic module, for example, a thin film such as a semiconductor film or a metal film is formed on a substrate made of glass and having a transparent electrode formed on it.
When the thin film is formed on the substrate, particles may be attached to the substrate. If this happens, defects will develop. Therefore, the substrate is usually washed before the thin film is formed on the substrate in order to remove the particles.
When the washed substrate is left to stand and is thereby dried, the washing liquid attached to the substrate may form a water mark (stain). The substrate is therefore forcibly dried after the washing.
To dry the washed substrate, a clean oven is used in a conventional method. The clean oven is designed such that clean air is introduced into the interior. In the clean oven, the air is heated by a heater and circulated.
Therefore, if the washed substrate is placed in the clean oven, it can be dried with the heated air circulating in the clean oven.
As indicated above, the clean oven is designed to dry the substrate while the heated air is circulated, oven is clean, hence, the air gradually contain with particles remaining in the clean oven even if it is clean when introduced into the clean oven.
It is therefore easy for particles to attach to the substrate dried in the clean oven. Consequently, defects are likely to develop in the thin film formed on the substrate.